Magnetic tape recording/reproducing systems are widely used to record and reproduce analog and digital audio and video information and digital data information. The magnetic tape is usually stored on a reel or reels which typically are contained in a two reel cassette. The cassette is adapted to be inserted into and removed from a magnetic tape recording/reproducing apparatus, such as a helical scan magnetic tape recorder. In such case, it is desirable that the cassette be easily inserted or removed from the recorder. At the same time it is desirable that the cassette be locked in position during recording and reproducing, since during these operations, magnetic tape is removed from the cassette and transported along a path past rotating magnetic heads of the helical scan recorder. If the tape cassette is not locked during such operations, movement of the cassette can damage or destroy the tape, resulting in loss and destruction of the data recorded on the tape.